Anthropic PBC, a prominent player in the artificial intelligence sector, has issued a warning to investors regarding unauthorized sellers of its shares. The company identified eight firms, including Hiive and Forge Global, that are offering shares in violation of its transfer restrictions. This update follows a previous blog post where Anthropic cautioned about stock scams and fraudulent share certificates. The rise of secondary marketplaces has made it easier for employees and early investors to sell shares of private companies, particularly as startups remain private longer and achieve significant valuations. Anthropic has been strict about its policies, prohibiting the use of special purpose vehicles (SPVs) for share transactions. The company also advised investors to be wary of unsolicited offers and payments in cryptocurrencies, as these are often linked to fraudulent activities. In light of these concerns, Anthropic is actively working with some platforms to clarify its position and protect its investors.